Solid pseudopapillary tumor of the pancreas (SPT) is an extremely rare neoplasm of the pancreas, accounting for only 1% to 2% of pancreatic neoplasms. An SPT is a tumor of the primitive pancreatic epithelial cells, with predominance of exocrine features but having the capacity for dual (exocrine and endocrine) differentiation.1 Solid pseudopapillary tumor of the pancreas usually occurs in young girls, with more than 50% of patients younger than 19 years,2 and are more common among black and Asian populations.3 Many of these tumors are asymptomatic and present as mild abdominal pain and a lump.

The characteristic sonographic findings of SPT are a well-encapsulated, cystic, and solid mass. Sometimes the mass looks solid, or it may have internal septations or calcifications.4 Contrast-enhanced computed tomography will show a large, hypodense lesion with a few low-attenuation areas. Because of such findings, these lesions are often mistaken for pseudocysts.5

Treatment of SPT includes the Whipple procedure for masses found at the head of the pancreas and distal pancreatectomy for distal growth.3 Solid pseudopapillary tumors of the pancreas usually grow slowly; however, metastasis to the liver and peritoneum has been described.6,7 The most distinctive feature on histopathologic examination is pseudopapillae covered by several layers of epithelial cells. Nuclei are ovoid and folded, with indistinct nucleoli and few mitoses. Hyaline globules and a collection of foam cells may be present.8 Solid pseudopapillary tumors of the pancreas show strong cellular immunoreactivity for vimentin and focal, weak keratin reactivity. Neuron-specific enolase, α1-antitrypsin, and α1-antichymotrypsin stains are also positive.9